California Code, Labor Code - LAB § 2800.1

An employer shall in all cases take reasonable and necessary precautions to safeguard musical instruments and equipment, belonging to an employed musician, located on premises under the employer's control.  In the event such equipment is damaged or stolen as a result of the employer's failure or refusal to take such reasonable and necessary precautions, the employer shall be liable to the owner for repair or replacement thereof if the employed musician has taken reasonable and necessary precautions to safeguard the musical instruments and equipment.

For the purposes of this section:  (a) “employer” includes a purchaser of services and the owner of premises upon which an employed musician is working;  and (b) “employee” is any employed musician working on premises which are under an employer's control.